Teodora Kostovic isn’t interested in talking about her tennis strokes.

“Forehand, backhand, slice, drop shot all of that, I have that,” the 17-year-old Serbian standout said.

No, what’s most important to the teen is the mental part of tennis, the side no one sees but has been talked about more and more.

Kostovic used to be a mess, she said. Crying on the court, banging her racket, unable to control her emotions when things were going badly in a match.

But over the past two years Kostovic has been working with a sports psychologist who is helping her immensely.

“I am learning to play every point and be in the moment, that’s where my efforts have been going,” Kostovic said. “Don’t look at future, don’t look at past, just be in the present moment and enjoy that.

“Some people who know me now, they say ‘oh my God Teodora on the court, you have like a poker face,’” Kostovic continued. “They didn’t know me before when I would act crazy.”

Living in the present is good advice, and certainly good advice if your present has been as good as hers.

Working her way up to No. 6 in the ITF Junior rankings, Kostovic has had an outstanding 2024. She won J300 Roehampton in June and captured the title at J300 College Park in the United States in August, and reached the finals at J500 Offenbach and J300 Indian Wells.

Kostovic also reached the Wimbledon quarter-finals where she lost to world No. 3 American Iva Jovic, who Kostovic had defeated at Roehampton.

“She’s a really tough player and really one to watch in this draw,” Jovic said. “She’s on a win streak and mentally she’s strong. She fights well, doesn’t roll over. Definitely tough to play.”

Kostovic said she’s brimming with the most confidence she’s ever had, and her answers to interview questions certainly show that.

After defeating Mia Pohankova 7-6, 6-2 in the second round at the 2024 US Open Junior Championships on Tuesday, Kostovic explained why she’s so comfortable here in New York.

“I have an aunt who lives here, Dianna, for more than 20 years, so she comes to my matches and I love it,” Kostovic said. “Right now I’m just enjoying every moment on the court.”

Kostovic, whose penetrating groundstrokes pin opponents deep in the court, said she comes from a sports-obsessed family, and when she and brother Milos were little, their Dad told them to pick one sport to focus on.

So at age five Teodora chose tennis, and promptly told her father she was going to be No.1 in the world.

“And he said it’s OK, you don’t have to be number one, just always try your best,” Kostovic recalled. “But I told him no, I was going to be number one.”

For Kostovic, the belief comes from within.

“I always feel like I should’ve won, whatever tournament I play,” she said. “I know I can beat anybody on the tour, ITF, WTA, I always believe in myself.”

If Kostovic wins a few more matches here in New York, she will validate that belief. And she’ll finally allow herself something she really wants.

“I’ve had to cut cookies and sweets out of my eating, it’s been a long time,” she said, laughing. “But I told myself if I win a Grand Slam, I’m going to get lots of vanilla ice cream.”